One pin, RA4, is different; it is configured as an open drain MOSFET.
When set to low, it performs identically with the other pin architectures.
However, when set to high, there is no internal connection with VDD and
hence it will not directly source voltage. If it’s necessary to use RA4 as a
sourcing output pin, you can add an external “pull-up” resistor, typically in
the range of 470 ohms–4.7K ohms. The sourced current then comes from
the pull-up resistor. Unlike all other pins that cannot exceed VDD, RA4’s
open drain is rated to 12 volts.